Differential actuating mechanism



April 6, 1954 D. BRoxDo 2,574,408

DIFFERENTIAL ACTUATING MECHANISM Filed Deo. 26, 1951 s sheds-sheet 1 Inventor Attorney April 6, 1954 D. BRolDo 2,674,403

DIFFERENTIAL ACTUATING MECHANISM Filed Dec. 2e, 1951 s sheets-sheet 2 Attorney 3 Sheets-Sheet 3 Filed Dec. 26, 195] Attorney Patented Apr. 6, 1954 UNITED STATES PATENT OFFICE DIFFERENTIAL ACTUATING MECHANISM Daniel Broido, Barnet, England Application December 26, 1951, Serial No. 263,176

6 Claims. 1

This invention relates to adding, accounting, calculating and like machines employing resiliently driven value-entering means.

In machines of the kind referred to the values to be entered are often represented by settable stops; value-entering reciprocating racks or similar devices are yieldingly driven on to the stops, the distance covered by the racks when moving from a fixed starting position on to the stops being representative of the values associated with the respective stops. These racks may be driven by springs or similar resilient means, and the total force of these springs or like means represents a major factor of the load to be overcome by the drive of the machine, inasmuch as these resilient means must be sufliciently powerful to drive the racks at a relatively high speed.

The main object of this invention is to devise an arrangement for driving value-entering racks and like means reliably at a high speed, and with a minimum of effort.

In some machines of the kind referred to the settable stops are mounted on a carriage shiftable denominationally in relation to value-entering means; alternatively, the value-entering means and/or the registers controlled by the value-entering means may be displaceable transversely of the settable stops. In order to ensure a free movement of the carriage a clearance must be provided between the shiftable parts and the stationary parts of the machine.

An object of the invention is to provide a substantial gap between the value-representing stops and the reciprocating value-entering means when the latter are in a starting or retracted position.

Other objects will become apparent as the dei scription proceeds.

With these objects in view, according to the present invention, a value-entering device for use in machines of the kind referred to having selectively settable stops representing numerical values comprises a plurality of reciprocating elements normally located in a starting position, the distance between any stop and the associated reciprocating element when the latter is in the starting position being representative of the value associated with the respective stop plus unity, a common driving member adapted to drive all said elements positively from the starting position through a distance substantially representative of unity, and means for restoring the said elements positively into the starting position.

The device may further comprise resilient driving means associated with each of said elements and adapted to drive it yieldingly on to the respective settable stop.

In the accompanying drawings which illustrate a preferred embodiment of the invention:

Figure 1 is a longitudinal vertical section through the value-entering device substantially on line I-I of Figure 2,

Figure 2 is a transverse vertical section substantially on line II-II of Figure 1,

Figure 3 is a longitudinal vertical section substantially on line III- III of Figure 4 showing part of the operating mechanism, and

Figure 4 is a transverse vertical section on line IV-IV of Figure 3 also showing the operating mechanism.

In a preferred embodiment of the invention the value-entering means are in the shape of reciprocating sensing racks 20, Figs. l and 2, slidably mounted in guides 2I-24. Each rack 20 is adapted to operate a numeral wheel l0 of a totalizer fully described in the specification to my co-pending application No. 263,177, now Patent INo. 2,628,029, the same numerals being used both in this co-pending specification and in the present application with reference to the same parts.

The values to be sensed by the racks 2e are represented by selectively settable stops shown somewhat diagrammatically in Fig. l as at t-S. When raised into position indicated by dotted lines, any stop 0 0 is adapted to intercept the tip 26 of the respective rack 20 when the latter is moved by its spring I9 to the left as viewed in Fig. 1. It will be understood that there is a bank of stops 0-9 in association with each operative rack 20; alternatively, one stop may be settable to each position 0 9 in association with each operative rack 20. Stops 0 0 may be operated in various manners which are well known in the art and immaterial for a proper understanding of the present invention; for instance, they may be set in the manner described in my prior British patent specification No. 577,330.

According to the present invention, the distance between the stops ll-S. and the racks 29 when the latter are in the starting position is determined in the following manner:

Assuming the rack movement required to move the associated totalizer element Il) through a distance representative of unity is what may be termed one step, the distance from the tip 25 of a rack in the starting position of Fig. l to a stop representing Il is made equal to one step, that to a stop representing I is made equal to two steps, that a stop representing 2 is made equal to three steps, and so on; the distance from a rack to a stop representing 9 is ten steps. Thus, the distance between a rack in starting position and a stop is equal to the value represented by the stop plus unity. When the racks are in the starting position, the minimum gap G between the racks and the stops is one step. Thus, if theA value associated with a stop is N, then the distance A from a rack in the starting position to this stop is made equal to: A=N+ 1.

Racks 20 are maintained in their starting position against the tension of their springs I9 by a restoring bar 25. At the start of the valueentering operation the restoring bar 25 is moved quickly to the leftv as viewed in Fig. l, in a man.- ner fullyv described hereafter, and at` the same time a driving bar II moves to the left so as todrive the racks 2li` positively across the gap G. This movement` of the drive bar is relatively fast; it serves to` accelerate the racks rapidly and to send them positively on their way towards the'settable stops Il-Qf. Drive bar |110- comes to a stop after having pushed the racks one step, and the racks continue to move towardsl the stops due partly to inertia and partly to.` their springs I9. When a rack tip 26 reaches the associated stop, the rack comes to a rest; any rebound may be prevented by a ratchet pawl I1I rockable on a shaft I12 under the influence of a spring |13. Prior to the return stroke` of the racks. 20 the ratchet pawls I1I are disengaged from the racks by av cross-bar IH, in a manner to be described indue course; the restoring crossba-r 25. andthe driving bar move back, and the restoring bar 25 picks up the racks 2n and restores them to the starting position, preferably againstr a iixed stop bar (not shown).

As the original inertia of the racks is overcome by the driving bar I1U, the` springs I9 attached to the racks have to overcome only the frictional resistance of the racks and associated parts, and the drag of the rebound pawlsy I1I-. Consequently, these springsV I9` may be relatively weak, and the total load may be` considerably reduced in comparison with a conventional arrangement wherein the springs have to overcome the original inertia of the. driven` parts. If the driving bar |10 is sumciently fast, the acceleration appliedy to the racks 20 may be sufficient to propel the racks through the remainder of their stroke, and the springs I9 may be omitted altogether. If desired, thereV may be a gap between the driving bar andthe racks when in the starting position, and the driving bar |10 may move more than one step in order to produce a hammer-like action and toy accelerate thel racks rapidly.

As shown in Figs. 1 and 2, a gear I1 is arrangedA adjacent to each rack 2B; gears I1 are rotatable on shaft I8 lixedly supported in the machine structure I2, I3. Each gear I1 meshes with a pinion I5 fixed to a totalizer wheel I0 rotatable on a shaft` Il. The teeth on gears I1 and racks 2|) have the. same pitch; therack pitch line is tangential to the gear pitch circle, and

normally a gap between two rack teeth is aligned with a gap between two gear teeth, the gears I'l being held in this position by means fully described in my said copending specification. Pinions 21 are rotatably mounted on a shaft 28 xedly held in a support 29; one pinion 21 is aligned with each gear I1 and rack 20 as shown in Fig. 2, and its width is approximately equal to the combined Width of gear I1 and rack 20. Pinions 21 are normally held by a stationary aligner bar |15 in such a position that a tooth on each pinion points towards the said aligned gap between two adjacent teeth on the respective; gear I1 anclv rack 20,. the pi'nions being just out of mesh with gears and racks. In order to couple racks 20 to gears I1, pinion shaft 28 is moved bodily upwards, in a manner fully describedy hereafter, so that a tooth on each pinion 21 enters the said gap between teeth on the associated gear and rack. When pinions 21 are fully in mesh with. gears and racks, they are free of the aligner |15; thus, a driving connection is established between racks 20 and gears I1.

Prior to an additive value-entering operation pinions` 21 couple-racks ZIIto gears. tf1, whereupon racks 20 are caused to move on to stops: Ilz-0. as. described, thereby driving` the totalizer wheels Illadditively (anti-clockwisev as viewed in. Fig, l) in accordance with the values represented by the respective: stops plus unity. At. thev end of for.- ward stroke of racks 2l)` pinions 21- are, demeshed from racks 20 and gears I1, whereupon racks. 241 are restored to their starting position by the re-r storing bar 25. During a subtractive valuefentry pinions 21 couple racks 20 to gears I1 only after the forward stroke of racks` 2.0, so thatv racks 20. drive during their. return stroke the. totalizer wheels I0 subtractively (clockwise as viewed in Fig. 1)

On completion, of the valuefentering opera.- tion the carry is effected. in. a manner fully de.. scri-bed in the specication to my said co-pending patent application. It is suilicient to. state here that during the carry operation those totalizer orders which do notl require a, carry. are moved back one step, since all` values to bey entered into the totalizer have been automatically increased by unity due to the provision of the gap G, as described above. Those totalizer orders which do require. av carry remain stationary during the carry operation, since they have been already advanced one step in excess of the actual value to be entered..

As it is well, known. in the art of calculating machines, racks 20 and settable stops 0-9 may be arranged to be relatively displaceable transversely of the machine; in such a casev the. provision of a susbtantial gap G according to the present invention is of. advantage. in order to facilitate this transverse displacement.

The operating mechanism will now be described. The machine is operated by a. main driving shaft 16, Figs. l and 4, suitably journalled in the supporting structure I2,l 11 and rotated once during each operating cycle by a suitable handle or motor (not shown).

Referring to Fig. 3, the mesh-demesh operation of pinions 21 is controlled by a grooved cam 1B fixedly mounted on main shaft 1B. Cam 18 co-acts with a roller 19 journalled in a follower fixedly mounted on a shaft 8'I journalled in the supporting structure 11, 82, Fig. 4. An arm 83, Fig. 3, is` fixedly mounted at each` endl of shaft 8|.; each` arm 83. has aA pinfand-slot. con.- nection 84 to a lever 85 rockable on a trunnion 86 fixedly supportedin machine frames 11, 82, Fig. 4, respectively. Pinion shaft support 29, Figs. 1 and 3, is xed at each end to one of levers 85. During addition the main driving shaft -16 is rotated clockwise as viewed in Fig. 3, and

early in the cycle cam 19 causes its follower 99 to rock anti-clockwise, which causes levers 35 and support 29 to rock clockwise around trunnions 86 and thus to mesh pinions 21 withjpgears |1 and racks 29, as described. The parts remain in this position until shortly before the racks 29 start'on their return stroke; now earn 13 restores follower 89 and support` 29', so that pinions are demeshed from racks 29. During subtraetion the main shaft 16 is rotated anti-clockwise; at about the middle of the cycle cam 19 rocks its follower 80 anti-clockwise thus meshing the pinions 21 with racks 29 and gears |1. Near the end of cycle cam 18 restores the follower 99, and pinions 21 are again demeshed from racks 20 and gears 1.

Driving bar |10 protrudes through slots in machine frames l2, I9 and is at each end secured to a bracket |16, Fig. 3, xedly mounted on a sleeve 92, Fig. 1, rotatable on shaft 8|. Fixedly mounted on sleeve 92 is an arm |11 which has a roller |18 maintained by a spring |19 in contact with a cam 80 xedly mounted on shaft 16. Cam |80 is so shaped that early in each operating cycle it causes the follower brackets |16 to rock sharply anti-clockwise around their shaft 8|; this results in a corre spending movement of driving bar |19, which starts the racks 29 on their forward stroke as described. An overthrow of driving bar |12) may be prevented by a fixed stop iti, 3. During the second half of cycle the cam |99 restores the driving bar |10. Cam |99 is symmetrical and operates the driving bar H19 in exactly the same manner during both additive and subtractive revolutions of shaft 1B.

Similarly, the restoring bar 25 is operated in like manner both by counter-clockwise and clockwise revolutions of main shaft 19. Restoring bar 25 protrudes through suitable slots in inachine frames I2, |3, and is xed at each end to an angle bracket |82, Fig. 4, guided by rollers |83 in rails |94 secured to frames I2, i3, respectively. Each bracket |82 has a pin |35, see also Fig. 3, engaging a slot in an arm 99 xedly mounted on a shaft |81 suitably journalled in machine .frames l2, 11. A cam follower E99, Fig. 1, is iixedly mounted on shaft |91; it has two rollers |89 coacting with a double cam 99 xedly mounted on main shaft 19. When shaft 16 is turned in either direction, cam |99 causes shaft |81 and arms |85 to rock anti-clockwise. In consequence, brackets |82 and bar 25 are caused to slide to the left as viewed in Fig. 1, thus allowing the racks 29 to move during their forward stroke as described. Bar 25 reaches its extreme left-hand position shortly before the middle of cycle, and after a short space of time required for the mesh-demesh operation of idlers 21 described above, bar 25 is restored by its cam |99. As the bar 225 moves to the right, it picks up racks 2|! and restores them into their starting position.

As already mentioned, rebound-preventing pawls |1|, Fig. 1, are disengaged from racks 29 |11 and on shaft I4I. A spring |94 'anchored at |95 in the supporting structure normally presses the lower end |96 of latch |93 against a pin |91 secured in the double cam |90. Pawls |1| are normally in engagement with racks 20. Shortly before the rack restoring bar 25 reaches its extreme left-hand position (as viewed in Fig. 1), two abutments |98 on bar 25 contact extensions |99 of brackets |9| and cause the brackets to rock anti-clockwise. This causes bar |14 to rock around shaft |12 so as to disengage all pawls |1| from associated racks 20. At the same time latch |93, which is now not supported by its pin |91, rocks slightly due to spring |94 and latches the restoring bar 14 in the restore" position, in which it remains until the end of return stroke of racks 29. Shortly before the end of cycle pin |91 re-engages end |96 of latch |93 and rocks it slightly clockwise; latch |93 delatches bar |14 which releases the pawls |1|. Due to their springs |13 pawls |1| now re-engage the racks 20 in readiness for the next operating cycle.

It will be apparent to those skilled in the art that the device hereinbefore described may be readily modified Without departing from the spirit of the present invention. Thus, springs I9 driving the reciprocating racks 29 may be replaced by single or double resilient plungers or rockers `coi-acting with suitable abutments on the racks, or by suitable frictional devices. Straight-line racks may be replaced by rotary segments. In machines adapted for irregular numerical systems such as Sterling the actual size of the gap G between the various racks and the settable stops, and/or the amount of positive displacement applied to the racks associated with different denominations by the driving bar |19 or its equivalent, may be selected to suit the different conditions. The invention may be advantageously applied to reciprocating devices adapted to sense the presence or absence of settable stops.

What I claim is:

l. In a machine of the type referred to having selectively settable stops representing numerical values: a plurality of reciprocating elements normally located in a starting position, the distance between each element when in the starting position and the associated stop being representative of the value represented by the respective stop plus unity, a driving member for positively driving all said elements through a distance substantially representative of unity, individual resilient means each associated with one of said elements for yieldingly driving the associated element on to the respective stop, and a restoring member for positively restoring all said elements into the starting position.

2. A machine according to claim 1, further comprising means for preventing a rebound of the said elements when they contact their respective stops.

3. A machine according to claim 1, further comprising means for reciprocating the said driving member during each operating cycle at least through a distance representative of unity.

4. A machine according to claim 1, further comprising means for reciprocating the said restoring member during each operating cycle at least through a distance corresponding to the maximum stroke of any one of said elements.

5. In a machine of the type referred to having selectively settable stops representing numerical values: a value-entering device comprising a.

plurality of reciprocating elements arranged in 8 reaching the respective stops, and means for positively restoring the said elements into their starting position.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,108,476 Dahlberg Feb. 15, 1938 2,493,799 Anderson Jan. 10, 1950y FOREIGN PATENTS Number Country Date 218,922 Switzerland Apr. 16, 1942 

